They're tarring all cough medication with the same brush. What they're really talking about is cough medication that uses guaifenesin as the active ingredient. Guaifenesin is ineffective in reducing coughs. But that's not what it does. Guaifenesin thins mucus. Which just makes a cough more productive, but doesn't reduce the urge to cough.
So when the doctors say cough medicine is ineffective in reducing coughs, it's because the manufacturers have been using an ingredient for a purpose it's not intended and marketed it for something it doesn't do. So what's all the hoopla about? It's nothing new. It's not harmful....it just doesn't work. There's plenty of other stuff out there that doesn't work, too, and some of it IS harmful.
Furthermore, the mention that cough medicines that contain other active ingredients -- dextromethorphan hydrobromide (DM) and/or antihistamines (especially diphenhydramine hydrochloride) -- ARE effective in reducing cough symptoms is buried under the alarmism and the fine print.
It's another case of much ado about nothing....the medical community in cahoots with the news media makes a big fuss about something that's not new and not news. I suppose they have to justify their salaries somehow.